<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>
<script>
    var socket;
    //判断当前浏览器是否支持websocket
    if (window.WebSocket){
        //go on
        socket = new WebSocket("ws://localhost:7000/hello");
        //相当于channelReado, ev 收到服务器端回送的消息
        socket.onmessage = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + ev.data;
        }
        //相当于连接开启(感知到连接开启)
        socket.onopen = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = "连接开启了.."
        }
        //相当于连接关闭(感知到连接关闭)
        socket.onclose = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" +  "连接关闭了..";
        }
    } else {
        alert("您的浏览器不支持!")
    }
    //发送消息到服务器
    function send(message) {
        if(!window.socket) { //先判断socket是否创建好
            return;
        }
        if(socket.readyState == WebSocket.OPEN) {
            //通过socket 发送消息
            socket.send(message)
        } else {
            alert("连接没有开启");
        }
    }
</script>
    <form onsubmit="return false">
        <textarea name="message" style="height: 300px; width: 300px"></textarea>
        <input type="button" onclick="send(this.form.message.value)" value="发送消息"/>
        <textarea  id="responseText" style="height: 300px; width: 300px"></textarea>
        <input type="button" value="清空内容" onclick="document.getElementById('responseText').value=''"/>
    </form>
</body>
</html>